Sulfation is one of the most common modifications found on carbohydrate moieties of glycoproteins, and can play an important role in the biological function of a glycoprotein. For example, sulfated glycans are known to be involved in several biological recognition events such as lymphocyte homing and removal of pituitary hormones from circulation. Phosphorylation is another common modification on carbohydrates that can significantly affect the biological function of a glycoprotein. However, phosphate and sulfate groups have essentially the same mass (80 Da). As a result, it is often difficult to differentiate between sulfated and phosphorylated species. There is a need, therefore, for techniques that can detect sulfated and/or phosphorylated glycan species, and a particular need for techniques that can distinguish between the two.